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Ventilation of residential buildings in Alpine region: a comparison between natural, mechanical, and mixed-mode strategies
Avella F, Bonato P, Belleri A, Babich F
Many studies have shown how controlled natural ventilation has multiple benefits on the health of people and the buildings in terms of indoor air quality (IAQ) and thermal comfort, as well as on the energy consumption of the building.
However, unfavorable outdoor environmental conditions can limit the use of solely natural ventilation and, for this reason, it is often necessary to resort to mixed-mode ventilation. The aim of this research is to demonstrate the potential of mixed-mode ventilation strategies in comparison with the performance of controlled natural ventilation and mechanical ventilation applied separately, in the context of a dwelling located in a multi-family house in Bolzano (Italy) during the summer season. Dynamic simulations were performed, developing a room-by-room coupled thermal and airflow model of the dwelling in TRNSYS and TRNFLOW to characterize its thermal behavior and the natural airflows. The study analyzes and compares three different scenarios: (1) only controlled natural ventilation (CNV), (2) only mechanical ventilation (MVT), (3) a combination of the two (mixed ventilation strategies, MIX).
In this work, the controlled natural ventilation strategiesare designed with a twofold aim, which is (a) to improve the indoor thermal comfort, reducing the overheating risk thanks to ventilative cooling, and (b) to improve IAQ by removing indoor airborne pollutants coming from indoor sources.
The first results show that
(a) CNV effectively reduces the overheating risk, also achieving excellent IAQ levels;
(b) MVT allows acceptable IAQ conditions and good water vapor removal, while overheating could become an issue in terms of duration and intensity. In addition, there is the electricity consumption associated with MVT; (c) in most cases, mixed ventilation provides excellent performance in terms of IAQ and thermal comfort, compared with the former strategies. Overheating is well managed, and the electrical consumption of MVT is limited.
DOI: 10.13124/9788860461919
